May 22, 2007 - 2Octagon Services Ltd, Old Windsor, Berkshire, UK. Introduction and objectives. Avian intestinal spirochaetosis (AIS) is a disease of poultry ...
Abstract 39
BRACHYSPIRA SPECIES ISOLATED FROM UK POULTRY SAMPLES
Presented at the 4th International Conference on Colonic Spirochaetal Infections in Animals and Humans Prague, Czech Republic, May 20-22, 2007
J.R. Thomson1, B.P. Murray1, L.E. Henderson1, J. Thacker1, D.G.S. Burch2 1
Scottish Agricultural College, Veterinary Services, Penicuik, Midlothian, UK 2 Octagon Services Ltd, Old Windsor, Berkshire, UK
Introduction and objectives Avian intestinal spirochaetosis (AIS) is a disease of poultry resulting in ‘wet droppings’ due to increased faecal water content, wet litter and faecal staining of eggs. Delayed and/or reduced egg production is reported to be a consequence of the condition (2,6). AIS is caused by infection of the caeca and/or the colo-rectum by Brachyspira species. In Australian poultry production, B.pilosicoli and B.intermedia are reported to be the most common pathogenic species (4). Little is known about the prevalence or importance of Brachyspira species in British poultry farming and the aim of this paper is to present preliminary data of Brachyspira isolations from routine diagnostic specimens.
Brachyspira species involved in AIS. B.innocens is considered to be non-pathogenic in birds. The isolations of B.hyodysenteriae were from flocks situated in fairly close proximity to pig units. The significance of B.hyodysenteriae in poultry is uncertain as information on pathological findings associated with infection is lacking. In all cases, it was the only Brachyspira isolate recovered from the submissions. B.alvinipulli was identified in one submission and is considered to be pathogenic in birds. ‘Atypical’ Brachyspira species were those that could not be identified by the existing criteria. Their significance is unknown
Materials and methods Faecal samples from poultry with histories of ‘wet droppings’ were submitted from commercial farms over a wide geographical area of the UK for Brachyspira testing. The results span a period from October 2005 to March 2007. Submissions from individual farms ranged from a single sample of pooled faecal material, up to five samples of pooled faecal material. On receipt, each pooled sample was mixed to obtain a representative sub-sample. Brachyspira cultures were carried out as previously described (3,5), with plates incubated anaerobically at 42oC+1oC. Cultures that were positive for Brachyspira species were subcultured to purity, the degree of beta haemolysis recorded and biochemical testing performed (3).
Isolate
Results There were 102 submissions involving 273 samples; the majority (96 submissions) were from layers. Of the submissions from layer flocks, 24% yielded B.intermedia, 25% B.pilosicoli, 28% B.innocens, 4% B.hyodysenteriae, 6% ‘atypical’ Brachyspira species, 1% B.alvinipulli and 29% yielded no Brachyspira isolates (Table 1). The prevalence of organisms within samples were 16% B.intermedia, 14% B.pilosicoli, 14% B.innocens, 3.5% ‘atypical’ Brachyspira spp., 1% B.hyodysenteriae and 0.4% B.alvinipulli, while 54% were culture negative (Table 1). Results from broilers, turkeys and partridges were small. The results confirm that B.intermedia and B.pilosicoli are both prevalent in samples from layers with ‘wet droppings’. A difference in distribution of the species was noted between caged and freerange birds for a subset of the samples, as reported in a separate abstract (1). Epidemiological differences between housing systems could be important in relation to the
Table 1: Results of Brachyspira culture of faecal samples from layers with ‘wet droppings’ Submissions
(n=96)
No Negative
30
%+v e 29
B.intermedia
25 26 29 4 1 6
24 25 28 4 1 6
B.pilosicoli B.innocens B.hyodysenteriae B.alvinipulli ‘Atypical’
Samples
(n=257)
No 13 4 40 35 35 3 1 9
%+ ve 54 16 14 14 1 0.4 3.5
Conclusions (i). B.pilosicoli and B.intermedia were isolated from faecal samples of layers with ‘wet droppings’ in 25% and 24% of submissions respectively (ii) B.hyodysenteriae was isolated from four flocks situated in fairly close proximity to pig units. Acknowledgement Thanks are due to poultry veterinarians who supplied samples and flock information, and to the staff at SAC Edinburgh for excellent laboratory support. SAC receives financial support from the Scottish Executive, Environment & Rural Affairs Department. References 1. Burch, DGS (2007) Proc 4th Int Conf on Colonic Spirochaetal Infections in Animals and Humans, Prague, Abst 42. 2. Dwars, R.M., et al (1992) Avian Pathology 21: 559-568. 3. Fellström C. et al. (1997). J. Clin. Microbiol. 35, 462-467. 4. McLaren, A.J. et al (1997) Journal of Clinical Microbiology 26: 412-417. 5. Thomson, J.R. et al. (2001). Anim. Health Res. Rev., 2, 31-36 6. Trampel, D.W. et al (1994) Avian Diseases 38:895-898.
